Sphingenine- and sphingosine-1-phosphate, collectively called sphingosine-1-phosphate (SPN-1-P), have been known for many years as products of sphingosine (SPN) kinase {Stoffel W., Hoppe-Seyler's Z. Physiol. Chem., 354: 562, 1973; 354:1311 (1973); Stoffel W., et al, ibid, 355:61 (1974); 354:169 (1973); Louie D. D., et al, J. Biol. Chem., 251:4557 (1976)}. The reaction catalyzed by sphingosine (SPN) kinase is regarded as an initial step of sphingoid base degradation to yield ethanolamine-1-phosphate and a long-chain aldehyde (e.g., palmital) by a pyridoxal phosphate-dependent lyase reaction (see FIG. 1). While SPN-1-P has been recognized as an initial catabolic product of SPN, the real physiological function of this compound has been unknown. SPN-dependent stimulation of mouse 3T3 cell growth has been shown to be independent of the protein kinase C (PKC) pathway {Zhang et al, J. Biol. Chem., 265:76 (1990)}, and has been attributed to formation of SPN-1-P {Zhang et al, J. Cell Biol., 114:155 (1991)}. SPN-1-P may enhance cytoplasmic Ca.sup.2+ release in analogy to the effect of inositol-1,4,5-triphosphate on Ca.sup.2+ movement {Ghosh et al, Science, 248:1653 (1990)}. Although SPN-1-P was assumed in these earlier studies to induce a cell-proliferative effect of 3T3 cells, particularly in the presence of epidermal growth factor and insulin {Zhang et al (1991)}, the physiological functional role of SPN-1-P in cells has been unknown.
On the other hand, SPN-1-P is difficult to synthesize from chemical reactions. B. Weiss {J. Am. Chem. Soc., 79:5553 (1957)} was able to synthesize dihydrosphingosine-1-P (sphinganine-1-P) but not sphingenine-1-P. This effort to chemically synthesize SPN-1-P was unsuccessful, probably because of the presence of multi-functional groups in SPN. The only reported method for preparation of SPN-1-P (mainly D-erythro isomer, but containing a small amount of L-threo isomer) is by treatment of sphingosylphosphocholine with phospholipase D, isolated from Streptomyces chromofuscus {van Veldhoven P. P., Fogelsong R. J., Bell R. M., J. Lipid Res., 30:611 (1989)}.